Prescribed burn set for Santa Rosa Plateau

The Santa Rosa Plateau Ecological Reserve near Murrieta is scheduled to close to the public Wednesday and Thursday, as authorities purposely burn about 200 acres to clear unwanted, exotic vegetation.

Reserve Manager Carole Bell said two separate "prescribed burns" are to be conducted by the California Department of Forestry and Fire Protection, or CalFire, near Fault and Waterline roads in the park's interior.

The plan is to burn vegetation between 6:30 a.m. and noon both days and smoke is expected to be visible across a wide swath of Southwest County. Depending on smoke conditions, closures could extend to later in the week.

Bell said the intentional burning is part of a long-range campaign to improve the already mostly natural 9,300-acre reserve.

"We are still very well-known throughout the state as having the best example of native bunchgrass prairies," she said.

But Bell said parts of the reserve, which also is known for its oaks and seasonal vernal pools, are overrun with plants that don't belong. That includes the Burro Mesa area that is 2 miles south of the visitor center and the target of one of the burns.

"The lower Burro Mesa was last burned in 2005 and has a history of invasion by artichoke thistle," she said. "After the (prescribed) fire in 2005, the unit actually exploded in artichoke thistle because the seed bank responds to fire."

In the years since, reserve staffers and volunteers have been digging out the invasive, nonnative plants and killing them with herbicides.

"After eight years, we are hoping to completely eliminate the seed bank with this fire and declare success against this weed," Bell said. "We will start restoring the unit with native seed next spring."

Bell said the second burn will target an area called the Clayhill unit, just west of Burro Mesa. She said it is one of the reserve's best examples of native plant diversity.

"We are burning to reduce the thatch layer, since this unit hasn’t been burned since 2002," she said. "This area should explode in wildflowers in 2014."